Electro-Harmonix Op-Amp Big Muff Pi Reissue fuzz, distortion, and sustainer pedal in black, orange, and silver finish.

I have not tested freshly myself before listing, it is sold as photographed and described.

The Op-Amp Big Muff Pi is Electro-Harmonix’s compact reissue of the late-1970s Big Muff circuit commonly referred to as the IC, V4, or Op-Amp Big Muff. Unlike the traditional transistor-based Big Muff circuit, this version uses operational amplifiers and three gain stages to produce its distinctive aggressive, compressed, and sustaining fuzz sound.

This version of the circuit is particularly associated with heavy alternative rock, grunge, thick rhythm sounds, sustained leads, and layered “wall of sound” guitar tones. Electro-Harmonix specifically links the original circuit with Billy Corgan and the Smashing Pumpkins’ Siamese Dream sound.

The pedal has controls for Volume, Tone, and Sustain. Volume controls the output level, Sustain adjusts the amount of distortion and sustain, and Tone ranges from bass-heavy sounds to brighter, more treble-focused settings.

The additional Tone switch removes the Tone control from the signal path for a more open, full-range sound. Electro-Harmonix improved this function over the original vintage pedal so that the output level remains approximately consistent when switching the tone circuit in or out.

The pedal uses true-bypass switching and is housed in a compact die-cast metal enclosure. It can be powered by a standard 9V battery or a compatible centre-negative 9V DC adapter.

The pedal is in very good cosmetic condition overall. The front graphics, knobs, toggle switch, LED lens, footswitch, input and output sockets, power socket, baseplate, screws, and rubber feet all appear intact.

There are visible light surface marks, dust marks, small scratches, and darker rubbing or handling marks on parts of the silver enclosure, particularly on the sides. These appear consistent with storage and handling rather than pedalboard use. There is no Velcro attached to the underside.

The original Electro-Harmonix box and the paperwork shown in the photographs are included. The box has visible storage wear, surface scratches, edge and corner wear, creasing, and a large old label or tape mark across the front.

Condition

• Very Good used condition
• Not freshly tested before listing
• Functionality can be confirmed before shipping if required
• No known pedalboard use
• No Velcro attached
• Silver, black, and orange enclosure presents well overall
• Light scratches, dust, rubbing marks, and storage / handling signs visible
• Darker cosmetic marks visible on parts of the side panels
• Front graphics remain clear and intact
• Volume, Tone, and Sustain knobs appear intact
• Tone on / off toggle switch appears intact
• LED lens and metal footswitch appear intact
• Input, output, and power sockets appear intact
• Baseplate, four screws, and four rubber feet are present
• Original box has scratches, creases, edge wear, corner wear, and label / tape residue
• No obvious broken or missing pedal components visible

Specifications

• Brand: Electro-Harmonix
• Model: Op-Amp Big Muff Pi Reissue
• Alternative Names: IC Big Muff, V4 Big Muff, Op-Amp Big Muff
• Effect Type: Analog fuzz / distortion / sustainer
• Finish: Silver enclosure with black and orange graphics
• Original Circuit Era: Circa 1978
• Reissue Release Year: 2017
• Reverb Model Years: 2017–2021
• Pedal Format: Standard compact pedal
• Circuit: Analog op-amp-based Big Muff circuit
• Gain Structure: Three gain stages
• Audio: Mono
• Controls: Volume, Tone, Sustain
• Volume Control: Adjusts the output level
• Tone Control: Ranges from bass-heavy to treble-focused sounds
• Sustain Control: Adjusts the amount of distortion, fuzz, and sustain
• Tone Switch: Removes the Tone control from the circuit
• Tone-Bypass Level: Designed to maintain a similar level in both switch positions
• Main Character: Aggressive, compressed fuzz with heavy sustain and pronounced crunch
• Suggested Styles: Alternative rock, grunge, heavy rock, shoegaze, sustained lead tones, and layered rhythm sounds
• Bypass: True bypass
• Indicator: Effect-status LED
• Footswitch: Effect on / bypass
• Input: 1/4" mono input jack
• Input Impedance: 55 kΩ
• Output: 1/4" mono output jack labelled AMP
• Power: 9V battery or compatible 9V DC adapter
• Power Polarity: Centre negative
• Recommended Adapter: Electro-Harmonix EHX9.6DC-200 or equivalent
• Minimum Adapter Capacity: At least 25 mA
• Current Draw: Approximately 5 mA
• Dimensions: Approximately 70 × 115 × 54 mm
• Construction: Compact die-cast metal enclosure

Included

• Electro-Harmonix Op-Amp Big Muff Pi Reissue pedal
• Original Electro-Harmonix retail box
• Original paperwork shown in the photographs
• Original internal packaging shown in the photographs
• No external power supply included
• No 9V battery included

Shipping

The pedal will be carefully packed in protective packing material inside an outer shipping box included in the item or shipping price.

Shipping will be via tracked courier service depending on destination, price, parcel size, and insurance availability. Tracking will be provided after dispatch.

International buyers are responsible for all import duties, VAT, customs fees, tariffs, brokerage / handling fees, and any other local taxes or charges required by the destination country. These costs are not included in the item price or shipping price.

Shipping outside Europe may be possible by prior agreement. Please contact me before purchasing for an exact insured courier quote.